Switch with elastic contacts



July 15, 1958 A. KREISINGER 2,843,709

SWITCH WITH ELASTIC CONTACTS Filed Dec. 27, 1956 3 Sheets-Sheet 1 INVENTOR. (fir/mi? r/1f: In e July '15, 1958 A. KREISINGER SWITCH WITH ELASTIC CONTACTS 3 Sheets-Sheet 2 Filed Dec. 27, 1956 INVENTOR. afrnaff .Yfre/s 013 er y 1953 A. KREISINGER 2,843,709

SWITCH WITH ELASTIC CONTACTS Filed D90. 27, 1956 I 5 Sheets-Sheet 3 I II ll United States 2,843,709 Patented July 15, 1958 ice SWITCH WITH ELASTIC CONTACTS Arnost Kreisinger, Suchdol, near Prague, Czechoslovakia, assignor to Tesla, narorlni podnik, Prague-Hloubetin, Czechoslovakia Application December 27, 1956, Serial No. 630,966

Claims priority, application Czechoslovakia December 31, 1955 6 Claims. (Cl. 200-166) The present invention relates to a switch, in particular to a switch with elastic contacts consisting of U-shaped springs.

The main object of the invention is to provide a switch showing the best possible qualities, while keeping its dimensions to a minimum.

A further object of the invention is to provide a high performance switch with a high insulating resistance, its own connecting members having a minimum induction and capacity.

A further object of the invention is to provide a switch which is simple in production and assembly, oiiers the possibility of replacing nonfen-ous metals by cheaper and more accessible material and provides also the possibility of various connections.

Another object of the invention is to provide a switch adapted for application for a plurality of purposes and arrangements, for example in the form of the so-called packet-switch.

With these and other objects in view, the switch according to the invention comprises a switch-body, adapted to receive the U-shaped resilient contacts in a position, in which their bent portions are arranged in the vicinity of the'axis of the switch, their elastic ends lying at the circumference of the switch-body.

Extensive practical tests have sh own that the wear of the operative component parts is negligible to such a degree, as to ensure an extraordinarily high reliability of the switch in operation.

The accompanying drawings show by way of example several embodiments of the invention in a diagrammatic representation.

Fig. 1 shows the rotatable switch-body in a side view, partly in section,

Fig. 2 is the corresponding plan View,

Fig. 3 shows a partial cross section of the switch-body according to Fig. 1 on a larger scale,

Fig. 4 shows the stationary switch-body in a side view, partially in section,

Fig. 5 is a plan view of the switch-body corresponding to Fig. 4,

Fig. 6 is a view, partly in section, of a detail of the stationary switch body according to Fig. 4,

Fig. 7 is an axonometric View of a spring, the planes in which the spring is bent being diagrammatically represented,

Fig. 8 shows in a plan view the inter-engagement of the contacts on a larger scale,

Fig. 9 shows in a side view the rotatable switch body with a modified arrangement or" the contacts,

Fig. 10 is a plan view of the switch body correspondingto Fig. 9,

Fig. 11 shows a detail of a modification according to Fig. 9 on a larger scale and Fig. 12 shows a multiple design of the switch according to the invention, the individual component parts of the switch being shown separately.

Before describing in detail the switch according to the invention it should be noted, that the expressions stationary and rotatable" bodies, denoting various parts throughout the ensuing specification are understood as being interchangeable within the framework of the invention, so that the stationary body in the disclosed example may be rotatable in another design and vice versa. The rotatable member may, of course, be used also as a stationary member.

In the example to be described now, a rotatable body 1 is used, said body carrying a set of contacts 2 rigidly inserted therein. Arranged in a stationary body 3, are elastic contacts, one of which is shown on a larger scale in Fig. 7. The two bodies 1 and 2 are arranged on a common axis. The mechanism necessary for rotating the body 1, including a ratchet wheel and other auxiliary arrangements being not the subject matter of the present invention have been shown only diagrammatically in Fig. 12.

The greatest possible elastic length of the resilient con-- tacts is of the utmost importance for the correct operation of the switch. This requirement is complied with according to the invention, While retaining minimum dimensions of the switch, by embedding the resilient contacts 4 in the switch body 3 so as to place their bent portions 41 to the vicinity of the axis of rotation A of the switch, whereas the elastic ends 42 of the same contacts are placed at the circumference of the switch body 3.

Secured to the opposite end of the resilient contact 4 is a current supply member 43. At this point a bent portion 44 is also provided, said bent portion retaining by means of its elasticity the corresponding end of the contact 4 in a groove in the switch body 3. The contact 4 has therefore two elastic bends. In order to secure their independence, the said bends are arranged in such a way that the plane M of the bent portion 41 placed in the vicinity of the axis A of the switch is substantiall perpendicular to the plane N, containing the bent portion 44 of the end of the contact 4 in the point of the current supply 43.

The embedding of the contact in the body 3 is intention ally carried out in a way to ensure not only the elasticity of the contacts to be fully effective, but also to secure the position of each individual contact. Three separate recesses 31, 32, 33 (see also Fig. 6) are provided in the body 3 for each contact 4, said recesses securing the position of the contact, namely in the point of current supply 43 in the point 41 in the vicinity of the axis A of the switch and in the point where the free elastic end 42 of the contact 4 is adapted for swinging movements. The body 3 is provided with a central bore 30, through which each contact 4 is passed and then inserted into the corresponding recesses 31, 32 and 33. In order to facilitate the assembly, the position of the contact 4 in.- serted into the recess 33 may be secured by means of any suitable cement or putty 34.

The shape of the contact 4 is also of advantage with a view to the desirable small induction resistance, which is important in particular when the switch is used for high frequency circuits. The portion 41 of the contact being bent, two prongs are thus produced on each contact, the two prongs representing a bi-filar winding with a minimum induction resistance. The advantages of con tacts consisting of wires (as shown and disclosed above) will be dealt with at a later stage.

The other set of contacts is secured to the body 1. According to the connection diagram, shown in the drawing the contacts of this set are'arranged so as to bridge the contact pairs 4 of the first set ofcontacts. Each of the contacts 2 of the second set has two bent ends 21, 21 (see Fig. 3) which are inserted into corresponding bores 11 in the body 1. These bores are preferably of conical formation, theends 21', 211 of the" contact 2 resting against 3 their walls and being retained therein by the elasticity of the contact 2. If required, the ends may be cemented in their position by a cement or putty T2. The central portion of the contact 2 does not rest closely against the body l, but is slightly deflected by the length D. This ensures a certain resiliency also of the contact 2.

The way in which the two contacts 2 and 4 touch each other in the assembled switch is shown diagrammatically in Pig. 4. The contacts 4 are embedded in the body 3 substantially in radial direction. If the other contacts 2 were provided on a circle with the centre in the point A, the point P in which the contacts touch, would remain permanently in the same place during the rotation of the two bodies 1 and 3 against each other. A considerable wear or the contacts 4 would thus occur in this point. For this reason the two contacts are secured according to the invention in such a way, that in the course of rotation of the two contact sets against each other, the points F, in which the two contact sets touch, are displaced along the contacts of both contact sets. In this way a restricted local wear of the contacts 4 is avoided. Fig. 8 shows an example of such a design in which the contacts 2 are placed under an inclination.

The contacts being made of wire, show several advantages, such as a reduction of the capacity of connecting parts. Further there is an advantageous increase of the specific pressure in the point of contact (which is, strictly speaking, a geometrical point), resulting in an extremely low transition resistance. With a view to the fact that the contacting point on both contacts is displaced under a high specific pressure, the surfaces of the contacts are rubbed against each other, ensuring thus the contact surfaces to be kept in clean condition. Moreover, a material which becomes highly polished by the said rubbing action may be used intentionally for the wires or for their surface. Further it is possible to transfer in this way the material of one wire to the surface of the other wire.

When the switch is rotated, the contacts 2 and 4 travel over each other (see Fig. 3); the movement is facilitated substantially by the wire 4 of one set of contacts having a larger diameter than the wire 2 of the other set of contacts. Under these circumstances the initial contacting point T of the two wires 2 and 4 comes underneath the axis of the wire (having a larger diameter), facilitating thus the movement of the contact 4 on to the contact 2.

The invention comprises also such embodiments, where one set of contacts has the form of a foil or of another conductive layer permanently secured to the surface of one of the bodies.

Figs. 9 and 10 show in elevation and in plan view respectively such a modification, in which a segment-shaped foil 25 and a connecting foil 26 are secured to the body 1. The resilient contacts 4 provided on the other body 3 slide along said foils. The foils or the layers 25 and 26 are very thin so that the movement of the contacts 4 when striking their edges, proceeds without any difiiculty whatsoever. The foils or the layers have, of course, to be secured to the surface of the body 1 by pressure or the like.

Both bodies 1 and 3, including the corresponding contacts-as described above--represent a so-called switchunit. A plurality of such units may be provided on a common axis A to product a packet switch.

Fig. 12 shows in a side view, partially in section, a packet switch of this type with two packets, the details of the switch being shown separated from each other. Each block comprises an insulating body 300, in which wire contacts 400 are embedded. According to the invention the elastic bend 402 is arranged in the vicinity of the axis A, whereas the contacting bent portion 501 is removed as far as possible from the axis A. All contact springs 400 of one body 300 are embedded in a common annular recess 302 and in separate slots 303. The opposite recess 301, which is also of annular formation,

4 serves as a mounting for the rotatable parts of the switch, said parts cooperating, however, with the neighboring switch unit.

The rotatable contacts have the shape of sheet metal strips and segments 200, which are reliably secured to an insulating disc by being inserted and bent in suitable slots. The disc 100 as well as the insulating ring 700 are provided with longitudinal slots 102 or 702 respectively, adapted to receive a flat extension 502 of the switch shaft The entire driving mechanism of the switch including the ratchet means is mounted in a housing 500. This mechanism being not the subject matter of the present invention, has not been shown in detail and will, therefore, not be described.

it hen all component parts as described above, are assembles, the extension 502 passes through all longitudinal slots 102, 702, 02 and 702. The whole assembly is then secured by screws 503, said screws extending on the one hand through the housing 500, on the other hand through a closure cap 6% and are tightened by nuts 504. To this end the component parts 390, 360 and 600 are provided with coaxial bores 365, 305 and 665. In the assembly spacing rings 505 are made use of.

The annular recess in the closure cap 600 is used for mounting the lower discs 100 and 700.

it is within the framework of the invention, particularly for special wirings, when for example an arrangement is used, in which one rotatable body 1 is made to cooperate with two stationary i. e. non-rotatable bodies 3, the body it being inserted between the two bodies 3, 3. If in such a case a conductive connection from one surface of the body 1 to its opposite surface is required, the conductive layer 27 may be extended over the edge of the body l. as indicated in Fig. 11.

The switch according to the invention has extremely small dimensions, a very high performance and reliability in operation. Considering its small dimensions, the switch is well suited for installing in restricted spaces (wireless receivers etc.). Its performance permits its use also as a power current switch.

I claim:

l. A switch comprising a switch body, resilient U-shaped contacts mounted in the switch body with their bends in the vicinity of the axis of the switch and their elastic ends at the circumference of the switch body, a second bend in each contact in the point of the current supply, a recess in the switch body, the said second bend being adapted to retain by its elasticity the end of the contact in the recess of the switch body, the plane of the first bend of the contact being substantially perpendicular to the plane of the second bend of the contact end placed in the point of the current supply.

2. A switch comprising a switch body, resilient U-shaped contacts mounted in the switchbody with their bends in the vicinity of the axis of the switch and their elastic ends at the circumference of the switch body, a second switch body adapted for cooperation with the said first switch body, at least one contact in the second switch body, conical bores in the second switch body, slanting end portions on each of the second named contacts, the said slanting end portions being inserted into the conical bores in the switch body.

3. A switch as claimed in claim 2 wherein the ends of contacts are secured in the conical bores by cementing.

4. A switch comprising a switch body, one set of resilient U-shaped contacts, each contact being mounted in the switch body with its bend in the vicinity of the axis of the switch and its elastic end at the circumference of the switch body, a second switch body, a second set of contacts consisting of a foil permanently secured to the surface of the second switch body for cooperation with the first set of contacts.

5. A switch as claimed in claim 4 wherein the second set of contacts consists of a conductive layer, permanently secured to the surface of the switch body.

6. A switch comprising a switch body, resilient said slanting end portions being inserted into the conical U-shaped contacts mounted in the switch body with their bores in the switch body the contacts being provided at bends in the vicinity of the axis of the switch and their both sides of the switch body. elastic ends at the circumference of the switch body, a second switch body adapted for cooperation with the said 5 Kefereilces flied in the file Of this Patent first switch body, at least one contact in the second switch UNITED STATES PATENTS body, conical bores in the second switch body, slanting r end portions on each of the second named contacts, the 2790939 Hoflache 1957 

